Rescue personnel have been working on the 40-meter wide sinkhole since Tuesday. Then, the hole in the Tokyo suburb of Yashio swallowed a truck and its driver, who has been stuck 15 meters down since then.
As time has passed, the hole has expanded and attempts to rescue the 74-year-old man have failed.
After attempting to lift the truck with a crane and digging, the rescue team has built a 30-meter long ramp that will be lowered to the vehicle.
We will remove the debris and rescue the driver as soon as possible, says regional governor Motohiro Ono according to AFP.
But time is running out, not least because up to 10 centimeters of snow is expected to fall in the coming days, writes Japan Times.
The man's health condition is unclear. He was reported to be awake and talking earlier in the week, but the rescue effort is being hampered by the unstable ground, which has also prevented communication with him.
The hole was initially 10 meters wide and 5 meters deep but has since grown rapidly, with earth and debris covering the truck's cabin.
The sinkhole is believed to have been caused by the collapse of the sewage system, and both rainwater and sewage have slowly begun to fill the hole.
To alleviate the sewage system, authorities have asked over a million residents in the surrounding neighborhoods to refrain from showering or bathing – or using washing machines, reports Japanese TV company NHK.
They have also started diverting sewage water to the nearby Edo River.
